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In the real world, the available information for evaluation is 
usually incomplete. Hence, some of the pertinent criteria have to be 
weighted down or bypassed entirely; an evaluation cannot be better 
then the available knowledge about the item to be evaluated. 
4. COMMON FEATURES 
The commonalities and differences of analytical and digital systems 
address the techniques, hardware, software, procedures and the ease 
of integration into larger systems. In the following, consideration 
is given to the commonalities of each of these items. 
4.1 Techniques 
The techniques strongly influence the procedures in geometric and 
semantic domains. They are determined by the selected methods and 
means (figure 2). 
Objec 
Techniques 
— Methods!-- — 
tives i- 
Required 
functions 
i 
Means j— 
Software - 
Human 
operator 
GI-base 
Hardware 
1 Concepts ' ' Resources 
1 State of the art 
Fig.2: Interrelationships of the constituents 
New means stem mainly from the achievements in the basic disciplines 
(see 2.1); they tend to dominate the methods and thus the 
operational procedures and the corresponding support. 
The techniques in the geometric domain are similar in analytical and 
digital systems. Differences pertain to the AD and DA image 
conversions, their storage, handling, communication and the 
displays; these are typical of digital systems. 
4.2 Hardware 
The hardware architectures and components of analytical and digital 
systems differ substantially, though they use similar geometric 
processors. 
Analytical systems are equipped with photo-stages, positioning and 
measuring devices and an optical observation system (figure 3).